Magnetic fuze



P 1951 J. R. BOYKIN 3,001,476

MAGNETIC FUZE Original Filed June 4, 1945 Detonator and ChargeWITNESSES: INVENTOR ATTORNEY United States Patent 8 Claims. (Cl.10270.2)

My invention relates to control devices and, in particular, to devicesto be mounted on bombs, projectiles, rockets and the like, and designedto act as antennas in conjunction with radio apparatus housed within thebomb, or the like. This application is a division of my applicationSerial No. 597,457 filed June 4, l945 now Patent No. 2,959,128 for aControl Device.

Many pieces of equipment have been developed in recent years in whichbombs, projectiles or other moving vehicles, are provided with radioapparatus which either radiate or receive energy from electromagneticfields external to the vehicle and employ it in conjunction with radioapparatus housed within the vehicle. In such cases, it is necessary toprovide some form of antenna on which the radiated or receivedelectromagnetic waves may react. However, the high speeds with which thevehicles travel through the air imposes many mechanical stresses onthese antennas and the design of an antenna, which will be mechanicallystable and able to resist the stresses of the air streams flowing pastthe surface of the vehicle, has proved to constitute a problem of gravedifliculty.

One object of my invention is, accordingly, to provide a form of antennaor electrical radiator suitable for mounting on bombs, or other rapidlymoving projectiles, or vehicles and which shall produce magnetic fieldshaving a desirable space distribution about the moving vehicle.

Another object of my invention is to provide a structure suitable forradio antennas mounted on bombs; projectiles, or other vehicles, adaptedto move at high velocity through the air.

A still further object of my invention is to provide a bomb, shell orother vehicle intended for rapid motion through the air, with means fortriggering an electric control circuit when the projectile closelyapproaches an object, such as a target.

Another object of my invention is to provide a bomb, shell or othermissile or the like, with means for creating a substantially steady orconstant magnetic field relative to said device and for detecting thepresence of objects moving within this magnetic field.

Still other objects of my invention will become apparent upon readingthe following description, when taken in connection with theaccompanying drawings, in which:

FIGURE 1 is a figure, partly schematic and partly a sectional elevtion,illustrating a structure suited to produce a magnetic field in theregion about a bomb and also to act as a receiving antenna therefor inaccordance with one modification of my invention; and

FIG. 2 is a figure of similar nature illustrating another modificationof my invention which embodies a permanent magnet and has a separatereceiving antenna.

Referring in detail to FIGURE 1, it shows an arrangement well adapted topermit a projectile 1 to be exploded by the reactions of a steady orconstant magnetic field set up by the projectile itself on objects intoproximity with which the projectile moves. Thus, the projectile may havea cap portion 1A of insulating material carrying a winding 2 which setsup a substantially steady or constant magnetic field when energized bycurrent flowing from a direct-current source 3 through a suitablecontrol 3,001,476 Cfi Patented Sept. 26, 1961 resistor 4, the winding 2being mounted on the nose of the projectile preferably with its axisaligned with the axis thereof. The terminals of winding 2 are coupledthrough'a capacitor 5 across the grid-to-cathode circuit of an electrontube 6,. The tube 6 has an anode 7, a cathode 8 and a control electrode9, all of a form wellknown in the electronic art. The tube 6 has itscathode 8 connected to its anode 7 through a voltage source 11 and acoupling winding 12 of a form well-known in the electronic art. Atrigger circuit 13 may be coupled by any means well-known in theelectronic art, for example, by electromagnetic induction, with thecircuit of the anode 7. The circuit 13 may, for example, constitute aportion of a trigger circuit of a detonator 14, of any type well-knownin the art, adapted to detonate a charge of explosives carried by theprojectile 1. The cathodei8 is connected to the grid 9 through aconventional grid resistor 15.

induced on the control electrode9 of the tube 6 may be made suflicientto cause sufficient current flow through .the winding 12 and the triggercircuit 13 to detonate an explosive charge within the projectile 1.Thedetonation of an explosive is mentioned merely as one possible way ofemploying the reactions in the output circuit of the tube 6, and suchreactions may be employed for any other desired control purposes.

In the modification shown in FIG. 2 a permanent magnet 21 is used to setup the magnetic field, and a separate antenna 22 of a type described andclaimed in my above-mentioned parent application, and consisting of astrap of conducting material bent around so that its opposite ends maybe secured by bolts 23 to the cap portion 1A of the projectile 1, whichlatter is similar to that already described in FIG. 1.

The opposite ends of the antenna 22 are respectively connected throughcapacitors 24 and 25, to the control electrode 9 and the anode 7 of atube 6 connected to circuits like those already described in FIG. 1.When arranged as so far described, the voltages generated in the antenna22 by electromagnetic reactions of the field due to magnet '21 areobviously capable of exciting the tube 6 and producing amplified controlefiects in apparatus connected to its output circuit. Thus the device ofFIGURE 2 operates in substantially the same way as the device of FIGURE1.

I claim as my invention:

1. In combination with a projectile intended for rapid movement throughthe air, means for generating a substantially steady magnetic fieldmounted on said projectile, an antenna means mounted on said projectileand comprising an open ended loop of strap material having itsrespective ends fastened to points spaced apart on the wall of saidprojectile, and an amplifier circuit within said projectile connected tothe antenna means and arranged to respond to eddy currents induced inneighboring objects by said magnetic field.

2. In combination with a projectile intended for rapid movement throughthe air, a winding supported on the movement through the air, a windingsupported on the nose of said projectile with one of its faces shaped tofit closely the surface of said projectile at its area of contacttherewith, an energizing circuit for supplying direct current to saidwinding, an amplifier tube having a control circuit and a load circuitwithin said projectile, and connections to impress voltage from saidenergizing cirquit on said control circuit, and a detonator for anexplosive charge in said load circuit.

"4. In combination with a projectile intendeded for rapid movementthrough the air, and adapted for detonation within a predeterminedproximity to a target, a source of power for setting up substantiallysteady or constant magnetic flux lines about said projectile, said fluxlines adapted to induce eddy currents in said target, an amplifiercircuit including a control circuit and a load circuit, a detonator insaid load circuit, and antenna means responsive to said eddy currentswhich are induced in said target and connected to govern said controlcircuit.

5. The combination with a projectile or the like of means secured tosaid projectile for creating a substantially steady magnetic fieldrelative to the projectile, and means including antenna means secured tosaid projectile for detecting eddy currents set up by said magneticfield in a body having conductivity and moving into proximity with saidprojectile.

6. A projectile having means secured thereto for creating a steady orconstant magnetic field relative to the projectile, and means secured tosaid projectile for detecting eddy currents set up by said magneticfield in an object having conductivity moving into proximity with saidprojectile, said detecting means comprising an antenna,

an amplifier circuit connected to the antenna, a trigger circuitconnected to the output of the amplifier so that when the projectilemoves into a predetermined proximity with said object, thetriggercircuit is activated.

7. The combination with a; project ile ota permanent magnet secured to.saicl pr,ojectile so as to 'create'a magneticfieldabont'theprojec'tile, I fthe projectile, an amplifyingcircuitconiiectedr to:tliefantenna, a triggering circuit connected totheampur m ei cuit so that when the projectile moves in sufiiciently'closeproximity with'a target that is a conductor, eddy currents are createdin the target by the magnetic field established by the permanent magnet,said eddy"curr ents induc'ing electromotive forces in the'aiite'nnawhich areamplifid by the amplifying circuit so as to actuate thetriggering circuit. A

8. The combination 'with ai'projectile of a-win'ding secured to saidprojectile, a'source of substantially-steady direct current connected tothe winding, amplifying 'circuit connected to the winding,thewindingalso 'serving as an antenna todetect eddy currents-establishedin an object which moves into'proxi'r'nityiwith the projectile, 'and atriggering circuit connected to the amplifier.

Re'fei'enc'es Cited in theme or this'p'atent UNITED STATES PATENTS2,398,801 Minkler 141 23, I946 2,400,551 .Hings ..May 21, 19:462,403,567 Wales July -9, '1946

